JavaScript 获取地址栏指定参数（整理）

假如当前地址栏链接为：https://test.com/?type=students&page=3
//获取参数方法1
function UrlSearch()
{
    var name,value;
    var str=location.href; //取得整个地址栏
    var num=str.indexOf("?");
    str=str.substr(num+1); //取得所有参数   stringvar.substr(start [, length ]
    var arr=str.split("&"); //各个参数放到数组里
    for(var i=0;i < arr.length;i++){
        num=arr[i].indexOf("=");
        if(num>0){
            name=arr[i].substring(0,num);
            value=arr[i].substr(num+1);
            this[name]=value;
        }
    }
}
var UrlSearch=new UrlSearch();   //实例化
alert(UrlSearch.type);   //students
alert(UrlSearch.page);   //3
alert(UrlSearch.studentid);   //undefined
//获取参数方法2---一般用这个
function getParameter(name) {
    var reg = new RegExp("(^|&)" + name + "=([^&]*)(&|$)");
    var r = window.location.search.substr(1).match(reg);
    if (r != null) {
        return decodeURI(r[2])
    }
    return null
}
alert(getParameter('type'));   //students
alert(getParameter('page'));   //3
alert(getParameter('studentid'));   //null
二、获取url链接对象取值
//转译
encodeURIComponent("https://zhidao.baidu.com");
//https%3A%2F%2Fzhidao.baidu.com
//逆转译
decodeURIComponent("https%3A%2F%2Fzhidao.baidu.com");
//https://zhidao.baidu.com
var url = decodeURIComponent(location.search); //包括问号;
// var url = 'https://api.zhongshi.cn/h5/login.html?{"type":"question","id":"67359","vip":true,"appid":"wx43992d7d489d8e53"}';
var indexOf = url.indexOf("?");
if (indexOf !=-1) {
  var a = url.substr(indexOf + 1);
  var obj = JSON.parse(a);   //这个是正确的转换
  console.log(obj,'34');
  appid = obj.appid;  //获取对象中某个参数值
}